In the production of recombinant antibodies useful as pharmaceuticals by using genetic recombinant technology, use of animal cells enables complicated post-translational modification and folding which prokaryotic cells are unable to perform. Therefore, animal cells have been frequently used as host cells for producing recombinant antibodies.
Recently, a great number of biological pharmaceuticals, such as antibodies and physiologically active proteins, have been produced. In particular, in antibody preparations where doses are usually on the order of milligram (mg) per administration, considerable amounts of antibodies are needed as active ingredients. Technologies that allow efficient production of recombinant antibodies by animal cells will lead to cost reduction of antibody preparations and promise stable supply to patients.
Therefore, more efficient methods of producing recombinant antibodies are desired.
In the preparation of a host cell for producing a recombinant antibody, one copy of a DNA encoding the heavy chain of the antibody and one copy of a DNA encoding the light chain of the antibody are usually transferred into the host cell (Non-Patent Documents Nos. 1 and 2).
[Non-Patent Document No. 1] Reff M E, Carner K, Chambers K S, Chinn P C, Leonard J E, Raab R et al. Depletion of B cells in vivo by a chimeric mouse human monoclonal antibody to CD20. Blood. 1994 Jan. 15; 83(2):435-45.
[Non-Patent Document No. 2] Presta L G Chen H, O'Connor S J, Chisholm V, Meng Y G; Krummen L, et al. Humanization of an anti-vascular endothelial growth factor monoclonal antibody for the therapy of solid tumors and other disorders. Cancer Res. 1997 Oct. 15; 57(20):4593-9.